Add changes to support different scale functions to convert adc code to
physical units.

Signed-off-by: Rama Krishna Phani A <rph...@codeaurora.org>
---
 drivers/iio/adc/qcom-spmi-vadc.c | 319 ++++++++++++++++++++++++++++++---------
 1 file changed, 249 insertions(+), 70 deletions(-)

diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c
index c2babe5..e605a9d 100644
--- a/drivers/iio/adc/qcom-spmi-vadc.c
+++ b/drivers/iio/adc/qcom-spmi-vadc.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2012-2016, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -84,7 +84,7 @@
 #define VADC_MAX_ADC_CODE                      0xa800
 
 #define VADC_ABSOLUTE_RANGE_UV                 625000
-#define VADC_RATIOMETRIC_RANGE_UV              1800000
+#define VADC_RATIOMETRIC_RANGE                 1800
 
 #define VADC_DEF_PRESCALING                    0 /* 1:1 */
 #define VADC_DEF_DECIMATION                    0 /* 512 */
@@ -92,6 +92,8 @@
 #define VADC_DEF_AVG_SAMPLES                   0 /* 1 sample */
 #define VADC_DEF_CALIB_TYPE                    VADC_CALIB_ABSOLUTE
 
+#define VADC_DEF_SCALE_FN                      SCALE_DEFAULT
+
 #define VADC_DECIMATION_MIN                    512
 #define VADC_DECIMATION_MAX                    4096
 
@@ -100,9 +102,43 @@
 
 #define KELVINMIL_CELSIUSMIL                   273150
 
+#define PMI_CHG_SCALE_1                                -138890
+#define PMI_CHG_SCALE_2                                391750000000
+
 #define VADC_CHAN_MIN                  VADC_USBIN
 #define VADC_CHAN_MAX                  VADC_LR_MUX3_BUF_PU1_PU2_XO_THERM
 
+/**
+ * enum vadc_scale_fn_type - Scaling function to convert ADC code to
+ *                             physical scaled units for the channel.
+ * %SCALE_DEFAULT: Default scaling to convert raw adc code to voltage (uV).
+ * %SCALE_THERM_100K_PULLUP: Returns temperature in millidegC.
+ *                              Uses a mapping table with 100K pullup.
+ * %SCALE_PMIC_THERM: Returns result in milli degree's Centigrade.
+ * %SCALE_XOTHERM: Returns XO thermistor voltage in millidegC.
+ * %SCALE_PMI_CHG_TEMP: Conversion for PMI CHG temp
+ * %SCALE_NONE: Do not use this scaling type.
+ */
+enum vadc_scale_fn_type {
+       SCALE_DEFAULT = 0,
+       SCALE_THERM_100K_PULLUP,
+       SCALE_PMIC_THERM,
+       SCALE_XOTHERM,
+       SCALE_PMI_CHG_TEMP,
+       SCALE_NONE,
+};
+
+/**
+ * struct vadc_map_pt - Map the graph representation for ADC channel
+ * @x: Represent the ADC digitized code.
+ * @y: Represent the physical data which can be temperature, voltage,
+ *     resistance.
+ */
+struct vadc_map_pt {
+       s32 x;
+       s32 y;
+};
+
 /*
  * VADC_CALIB_ABSOLUTE: uses the 625mV and 1.25V as reference channels.
  * VADC_CALIB_RATIOMETRIC: uses the reference voltage (1.8V) and GND for
@@ -148,6 +184,9 @@ struct vadc_prescale_ratio {
  *     start of conversion.
  * @avg_samples: ability to provide single result from the ADC
  *     that is an average of multiple measurements.
+ *@scale_function: Represents the scaling function to convert voltage
+ *     physical units desired by the client for the channel.
+ *     Referenced from enum vadc_scale_fn_type.
  */
 struct vadc_channel_prop {
        unsigned int channel;
@@ -156,6 +195,7 @@ struct vadc_channel_prop {
        unsigned int prescale;
        unsigned int hw_settle_time;
        unsigned int avg_samples;
+       unsigned int scale_function;
 };
 
 /**
@@ -197,6 +237,44 @@ struct vadc_priv {
        {.num =  1, .den = 10}
 };
 
+/* Voltage to temperature */
+static const struct vadc_map_pt adcmap_100k_104ef_104fb[] = {
+       {1758,  -40},
+       {1742,  -35},
+       {1719,  -30},
+       {1691,  -25},
+       {1654,  -20},
+       {1608,  -15},
+       {1551,  -10},
+       {1483,  -5},
+       {1404,  0},
+       {1315,  5},
+       {1218,  10},
+       {1114,  15},
+       {1007,  20},
+       {900,   25},
+       {795,   30},
+       {696,   35},
+       {605,   40},
+       {522,   45},
+       {448,   50},
+       {383,   55},
+       {327,   60},
+       {278,   65},
+       {237,   70},
+       {202,   75},
+       {172,   80},
+       {146,   85},
+       {125,   90},
+       {107,   95},
+       {92,    100},
+       {79,    105},
+       {68,    110},
+       {59,    115},
+       {51,    120},
+       {44,    125}
+};
+
 static int vadc_read(struct vadc_priv *vadc, u16 offset, u8 *data)
 {
        return regmap_bulk_read(vadc->regmap, vadc->base + offset, data, 1);
@@ -418,7 +496,7 @@ static int vadc_measure_ref_points(struct vadc_priv *vadc)
        u16 read_1, read_2;
        int ret;
 
-       vadc->graph[VADC_CALIB_RATIOMETRIC].dx = VADC_RATIOMETRIC_RANGE_UV;
+       vadc->graph[VADC_CALIB_RATIOMETRIC].dx = VADC_RATIOMETRIC_RANGE;
        vadc->graph[VADC_CALIB_ABSOLUTE].dx = VADC_ABSOLUTE_RANGE_UV;
 
        prop = vadc_get_channel(vadc, VADC_REF_1250MV);
@@ -468,27 +546,128 @@ static int vadc_measure_ref_points(struct vadc_priv 
*vadc)
        return ret;
 }
 
-static s32 vadc_calibrate(struct vadc_priv *vadc,
-                         const struct vadc_channel_prop *prop, u16 adc_code)
+static int vadc_map_voltage_temp(const struct vadc_map_pt *pts,
+                                u32 tablesize, s32 input, s64 *output)
 {
-       const struct vadc_prescale_ratio *prescale;
-       s64 voltage;
+       bool descending = 1;
+       u32 i = 0;
+
+       if (!pts)
+               return -EINVAL;
+
+       /* Check if table is descending or ascending */
+       if (tablesize > 1) {
+               if (pts[0].x < pts[1].x)
+                       descending = 0;
+       }
+
+       while (i < tablesize) {
+               if ((descending == 1) && (pts[i].x < input)) {
+                       /* table entry is less than measured*/
+                        /* value and table is descending, stop */
+                       break;
+               } else if ((descending == 0) &&
+                               (pts[i].x > input)) {
+                       /* table entry is greater than measured*/
+                       /*value and table is ascending, stop */
+                       break;
+               }
+               i++;
+       }
+
+       if (i == 0) {
+               *output = pts[0].y;
+       } else if (i == tablesize) {
+               *output = pts[tablesize - 1].y;
+       } else {
+               /* result is between search_index and search_index-1 */
+               /* interpolate linearly */
+               *output = (((s32)((pts[i].y - pts[i - 1].y) *
+                       (input - pts[i - 1].x)) /
+                       (pts[i].x - pts[i - 1].x)) +
+                       pts[i - 1].y);
+       }
 
-       voltage = adc_code - vadc->graph[prop->calibration].gnd;
-       voltage *= vadc->graph[prop->calibration].dx;
-       voltage = div64_s64(voltage, vadc->graph[prop->calibration].dy);
+       return 0;
+}
 
+static void vadc_scale_calib(struct vadc_priv *vadc, u16 adc_code,
+                            const struct vadc_channel_prop *prop,
+                            s64 *scale_voltage)
+{
+       *scale_voltage = (adc_code -
+               vadc->graph[prop->calibration].gnd);
+       *scale_voltage *= vadc->graph[prop->calibration].dx;
+       *scale_voltage = div64_s64(*scale_voltage,
+               vadc->graph[prop->calibration].dy);
        if (prop->calibration == VADC_CALIB_ABSOLUTE)
-               voltage += vadc->graph[prop->calibration].dx;
+               *scale_voltage +=
+               vadc->graph[prop->calibration].dx;
 
-       if (voltage < 0)
-               voltage = 0;
+       if (*scale_voltage < 0)
+               *scale_voltage = 0;
+}
 
-       prescale = &vadc_prescale_ratios[prop->prescale];
+static s64 vadc_scale_fn(struct vadc_priv *vadc,
+                        const struct vadc_channel_prop *prop, u16 adc_code)
+{
+       const struct vadc_prescale_ratio *prescale;
+       s64 voltage = 0, result = 0;
+       int ret;
 
-       voltage = voltage * prescale->den;
+       switch (prop->scale_function) {
 
-       return div64_s64(voltage, prescale->num);
+       case SCALE_DEFAULT:
+               vadc_scale_calib(vadc, adc_code, prop, &voltage);
+
+               prescale = &vadc_prescale_ratios[prop->prescale];
+               voltage = voltage * prescale->den;
+               return div64_s64(voltage, prescale->num);
+
+       case SCALE_THERM_100K_PULLUP:
+       case SCALE_XOTHERM:
+               vadc_scale_calib(vadc, adc_code, prop, &voltage);
+
+               if (prop->calibration == VADC_CALIB_ABSOLUTE)
+                       do_div(voltage, 1000);
+
+               vadc_map_voltage_temp(adcmap_100k_104ef_104fb,
+                                     ARRAY_SIZE(adcmap_100k_104ef_104fb),
+                                     voltage, &result);
+               result *= 1000;
+               return result;
+
+       case SCALE_PMIC_THERM:
+               vadc_scale_calib(vadc, adc_code, prop, &voltage);
+
+               if (voltage > 0) {
+                       prescale = &vadc_prescale_ratios[prop->prescale];
+                       voltage = voltage * prescale->den;
+                       do_div(voltage, prescale->num * 2);
+               } else {
+                       voltage = 0;
+               }
+
+               voltage -= KELVINMIL_CELSIUSMIL;
+
+               return voltage;
+
+       case SCALE_PMI_CHG_TEMP:
+               vadc_scale_calib(vadc, adc_code, prop, &voltage);
+               prescale = &vadc_prescale_ratios[prop->prescale];
+               voltage = voltage * prescale->den;
+
+               voltage = div64_s64(voltage, prescale->num);
+               voltage = ((PMI_CHG_SCALE_1) * (voltage * 2));
+               voltage = (voltage + PMI_CHG_SCALE_2);
+               return div64_s64(voltage, 1000000);
+
+       default:
+               ret = -EINVAL;
+               break;
+       }
+
+       return ret;
 }
 
 static int vadc_decimation_from_dt(u32 value)
@@ -552,11 +731,8 @@ static int vadc_read_raw(struct iio_dev *indio_dev,
                if (ret)
                        break;
 
-               *val = vadc_calibrate(vadc, prop, adc_code);
+               *val = vadc_scale_fn(vadc, prop, adc_code);
 
-               /* 2mV/K, return milli Celsius */
-               *val /= 2;
-               *val -= KELVINMIL_CELSIUSMIL;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_RAW:
                prop = &vadc->chan_props[chan->address];
@@ -564,12 +740,8 @@ static int vadc_read_raw(struct iio_dev *indio_dev,
                if (ret)
                        break;
 
-               *val = vadc_calibrate(vadc, prop, adc_code);
+               *val = (int)adc_code;
                return IIO_VAL_INT;
-       case IIO_CHAN_INFO_SCALE:
-               *val = 0;
-               *val2 = 1000;
-               return IIO_VAL_INT_PLUS_MICRO;
        default:
                ret = -EINVAL;
                break;
@@ -613,11 +785,13 @@ struct vadc_channels {
        },                                                              \
 
 #define VADC_CHAN_TEMP(_dname, _pre)                                   \
-       VADC_CHAN(_dname, IIO_TEMP, BIT(IIO_CHAN_INFO_PROCESSED), _pre) \
+       VADC_CHAN(_dname, IIO_TEMP,     \
+               BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_PROCESSED), \
+               _pre)   \
 
 #define VADC_CHAN_VOLT(_dname, _pre)                                   \
-       VADC_CHAN(_dname, IIO_VOLTAGE,                                  \
-                 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),    \
+       VADC_CHAN(_dname, IIO_VOLTAGE,                          \
+                 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_PROCESSED),\
                  _pre)                                                 \
 
 /*
@@ -637,12 +811,11 @@ struct vadc_channels {
        VADC_CHAN_TEMP(DIE_TEMP, 0)
        VADC_CHAN_VOLT(REF_625MV, 0)
        VADC_CHAN_VOLT(REF_1250MV, 0)
-       VADC_CHAN_VOLT(CHG_TEMP, 0)
+       VADC_CHAN_TEMP(CHG_TEMP, 0)
        VADC_CHAN_VOLT(SPARE1, 0)
        VADC_CHAN_VOLT(SPARE2, 0)
        VADC_CHAN_VOLT(GND_REF, 0)
        VADC_CHAN_VOLT(VDD_VADC, 0)
-
        VADC_CHAN_VOLT(P_MUX1_1_1, 0)
        VADC_CHAN_VOLT(P_MUX2_1_1, 0)
        VADC_CHAN_VOLT(P_MUX3_1_1, 0)
@@ -659,7 +832,6 @@ struct vadc_channels {
        VADC_CHAN_VOLT(P_MUX14_1_1, 0)
        VADC_CHAN_VOLT(P_MUX15_1_1, 0)
        VADC_CHAN_VOLT(P_MUX16_1_1, 0)
-
        VADC_CHAN_VOLT(P_MUX1_1_3, 1)
        VADC_CHAN_VOLT(P_MUX2_1_3, 1)
        VADC_CHAN_VOLT(P_MUX3_1_3, 1)
@@ -676,7 +848,6 @@ struct vadc_channels {
        VADC_CHAN_VOLT(P_MUX14_1_3, 1)
        VADC_CHAN_VOLT(P_MUX15_1_3, 1)
        VADC_CHAN_VOLT(P_MUX16_1_3, 1)
-
        VADC_CHAN_VOLT(LR_MUX1_BAT_THERM, 0)
        VADC_CHAN_VOLT(LR_MUX2_BAT_ID, 0)
        VADC_CHAN_VOLT(LR_MUX3_XO_THERM, 0)
@@ -690,42 +861,40 @@ struct vadc_channels {
        VADC_CHAN_VOLT(AMUX_PU1, 0)
        VADC_CHAN_VOLT(AMUX_PU2, 0)
        VADC_CHAN_VOLT(LR_MUX3_BUF_XO_THERM, 0)
-
-       VADC_CHAN_VOLT(LR_MUX1_PU1_BAT_THERM, 0)
+       VADC_CHAN_TEMP(LR_MUX1_PU1_BAT_THERM, 0)
        VADC_CHAN_VOLT(LR_MUX2_PU1_BAT_ID, 0)
-       VADC_CHAN_VOLT(LR_MUX3_PU1_XO_THERM, 0)
-       VADC_CHAN_VOLT(LR_MUX4_PU1_AMUX_THM1, 0)
-       VADC_CHAN_VOLT(LR_MUX5_PU1_AMUX_THM2, 0)
-       VADC_CHAN_VOLT(LR_MUX6_PU1_AMUX_THM3, 0)
+       VADC_CHAN_TEMP(LR_MUX3_PU1_XO_THERM, 0)
+       VADC_CHAN_TEMP(LR_MUX4_PU1_AMUX_THM1, 0)
+       VADC_CHAN_TEMP(LR_MUX5_PU1_AMUX_THM2, 0)
+       VADC_CHAN_TEMP(LR_MUX6_PU1_AMUX_THM3, 0)
        VADC_CHAN_VOLT(LR_MUX7_PU1_AMUX_HW_ID, 0)
-       VADC_CHAN_VOLT(LR_MUX8_PU1_AMUX_THM4, 0)
-       VADC_CHAN_VOLT(LR_MUX9_PU1_AMUX_THM5, 0)
+       VADC_CHAN_TEMP(LR_MUX8_PU1_AMUX_THM4, 0)
+       VADC_CHAN_TEMP(LR_MUX9_PU1_AMUX_THM5, 0)
        VADC_CHAN_VOLT(LR_MUX10_PU1_AMUX_USB_ID, 0)
-       VADC_CHAN_VOLT(LR_MUX3_BUF_PU1_XO_THERM, 0)
-
-       VADC_CHAN_VOLT(LR_MUX1_PU2_BAT_THERM, 0)
+       VADC_CHAN_TEMP(LR_MUX3_BUF_PU1_XO_THERM, 0)
+       VADC_CHAN_TEMP(LR_MUX1_PU2_BAT_THERM, 0)
        VADC_CHAN_VOLT(LR_MUX2_PU2_BAT_ID, 0)
-       VADC_CHAN_VOLT(LR_MUX3_PU2_XO_THERM, 0)
-       VADC_CHAN_VOLT(LR_MUX4_PU2_AMUX_THM1, 0)
-       VADC_CHAN_VOLT(LR_MUX5_PU2_AMUX_THM2, 0)
-       VADC_CHAN_VOLT(LR_MUX6_PU2_AMUX_THM3, 0)
+       VADC_CHAN_TEMP(LR_MUX3_PU2_XO_THERM, 0)
+       VADC_CHAN_TEMP(LR_MUX4_PU2_AMUX_THM1, 0)
+       VADC_CHAN_TEMP(LR_MUX5_PU2_AMUX_THM2, 0)
+       VADC_CHAN_TEMP(LR_MUX6_PU2_AMUX_THM3, 0)
        VADC_CHAN_VOLT(LR_MUX7_PU2_AMUX_HW_ID, 0)
-       VADC_CHAN_VOLT(LR_MUX8_PU2_AMUX_THM4, 0)
-       VADC_CHAN_VOLT(LR_MUX9_PU2_AMUX_THM5, 0)
+       VADC_CHAN_TEMP(LR_MUX8_PU2_AMUX_THM4, 0)
+       VADC_CHAN_TEMP(LR_MUX9_PU2_AMUX_THM5, 0)
        VADC_CHAN_VOLT(LR_MUX10_PU2_AMUX_USB_ID, 0)
-       VADC_CHAN_VOLT(LR_MUX3_BUF_PU2_XO_THERM, 0)
-
-       VADC_CHAN_VOLT(LR_MUX1_PU1_PU2_BAT_THERM, 0)
+       VADC_CHAN_TEMP(LR_MUX3_BUF_PU2_XO_THERM, 0)
+       VADC_CHAN_TEMP(LR_MUX1_PU1_PU2_BAT_THERM, 0)
        VADC_CHAN_VOLT(LR_MUX2_PU1_PU2_BAT_ID, 0)
-       VADC_CHAN_VOLT(LR_MUX3_PU1_PU2_XO_THERM, 0)
-       VADC_CHAN_VOLT(LR_MUX4_PU1_PU2_AMUX_THM1, 0)
-       VADC_CHAN_VOLT(LR_MUX5_PU1_PU2_AMUX_THM2, 0)
-       VADC_CHAN_VOLT(LR_MUX6_PU1_PU2_AMUX_THM3, 0)
+       VADC_CHAN_TEMP(LR_MUX3_PU1_PU2_XO_THERM, 0)
+       VADC_CHAN_TEMP(LR_MUX4_PU1_PU2_AMUX_THM1, 0)
+       VADC_CHAN_TEMP(LR_MUX5_PU1_PU2_AMUX_THM2, 0)
+       VADC_CHAN_TEMP(LR_MUX6_PU1_PU2_AMUX_THM3, 0)
        VADC_CHAN_VOLT(LR_MUX7_PU1_PU2_AMUX_HW_ID, 0)
-       VADC_CHAN_VOLT(LR_MUX8_PU1_PU2_AMUX_THM4, 0)
-       VADC_CHAN_VOLT(LR_MUX9_PU1_PU2_AMUX_THM5, 0)
+       VADC_CHAN_TEMP(LR_MUX8_PU1_PU2_AMUX_THM4, 0)
+       VADC_CHAN_TEMP(LR_MUX9_PU1_PU2_AMUX_THM5, 0)
        VADC_CHAN_VOLT(LR_MUX10_PU1_PU2_AMUX_USB_ID, 0)
-       VADC_CHAN_VOLT(LR_MUX3_BUF_PU1_PU2_XO_THERM, 0)
+       VADC_CHAN_TEMP(LR_MUX3_BUF_PU1_PU2_XO_THERM, 0)
+
 };
 
 static int vadc_get_dt_channel_data(struct device *dev,
@@ -802,6 +971,11 @@ static int vadc_get_dt_channel_data(struct device *dev,
                prop->avg_samples = VADC_DEF_AVG_SAMPLES;
        }
 
+       ret = of_property_read_u32(node, "qcom,scale-function",
+                                  &prop->scale_function);
+       if (ret)
+               prop->scale_function = SCALE_DEFAULT;
+
        if (of_property_read_bool(node, "qcom,ratiometric"))
                prop->calibration = VADC_CALIB_RATIOMETRIC;
        else
@@ -850,9 +1024,9 @@ static int vadc_get_dt_data(struct vadc_priv *vadc, struct 
device_node *node)
 
                iio_chan->channel = prop.channel;
                iio_chan->datasheet_name = vadc_chan->datasheet_name;
+               iio_chan->extend_name = child->name;
                iio_chan->info_mask_separate = vadc_chan->info_mask;
                iio_chan->type = vadc_chan->type;
-               iio_chan->indexed = 1;
                iio_chan->address = index++;
 
                iio_chan++;
@@ -964,16 +1138,21 @@ static int vadc_probe(struct platform_device *pdev)
        if (ret)
                return ret;
 
-       irq_eoc = platform_get_irq(pdev, 0);
-       if (irq_eoc < 0) {
-               if (irq_eoc == -EPROBE_DEFER || irq_eoc == -EINVAL)
-                       return irq_eoc;
-               vadc->poll_eoc = true;
-       } else {
-               ret = devm_request_irq(dev, irq_eoc, vadc_isr, 0,
-                                      "spmi-vadc", vadc);
-               if (ret)
-                       return ret;
+       vadc->poll_eoc = of_property_read_bool(node,
+                                               "qcom,vadc-poll-eoc");
+
+       if (!vadc->poll_eoc) {
+               irq_eoc = platform_get_irq(pdev, 0);
+               if (irq_eoc < 0) {
+                       if (irq_eoc == -EPROBE_DEFER || irq_eoc == -EINVAL)
+                               return irq_eoc;
+                       vadc->poll_eoc = true;
+               } else {
+                       ret = devm_request_irq(dev, irq_eoc, vadc_isr, 0,
+                                              "spmi-vadc", vadc);
+                       if (ret)
+                               return ret;
+               }
        }
 
        ret = vadc_reset(vadc);
-- 
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